andrewcs wrote:
GMATMadeeasy wrote:
Question : \(a^b^c\)
How one will interpret this ?\((a^b)^c\) or \((a)^(b^c)\)
Second :
\((81)^1/4\) ; It is equivalent to 3 and or -3 in GMAT ? I am aware that \(\sqrt{(x^2)}\) is always positive value.
You would interpret \(a^b^c\) as \(a^(b^c)\) - the rule is to work 'top-down'. To me, it would feel 'funny' to evaluation a^b before evaluation b^c.
The second one confuses me:
\(\sqrt{(x^2)}\) is x always positive?
Take \(x=-2\) for example:
\((-2)^2= 4\)
\(\sqrt{4}=+2, -2\), so x could have been either positive or negative.
Hence, \((81)^1/4\) is +3 or -3, but you cannot tell from the equation.
I concur with both the points you mentioned. However, for first point , that is top down approach of exponent, I will post a good question in a while to solve. For second point, refer to
GMAt Official guide , maths theory section ,it explicitly indicates that \(\sqrt{x^2}=|x|\) . I extended the definition further from x^2 to x^4.
I do not know what is the final answer .